How to calculate stress in a material, and also calculate how much it stretches?
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.sammiej. asked:
I’ve come acorss a problem, this is what i’m faced with.
A hollow steel tube has an external diamater of 100mm and a 80mm internal diamater, it is 3m long, and is subjected to a tensile load of 400kN. The stress of the tube needs to be calculated, and also, how much would the tube stretch if Youngs Modulus is 200 000 N/mm².
Thanks very much! Any help will be EXTREMELY appreciated.
Sam Lilley
September 8th, 2008 at 3:23 pm
Calculate the area of the tube. Then, the stress in the tube will be equal to the load divided by the area. The deflection of the tube will be equal to the load times the length divided by the product of Young’s modulus and the area.
September 10th, 2008 at 5:54 am
σ = stress = force/area
force = 400kN
area = [(100mm)^2 - (80mm)^2]∙π/4
σ = (400kN) / (900∙π mm^2)
σ = 444 N/mm^2
ε = strain = stress/youngs = σ/E
ε = (444 N/mm^2) / (200,000 N/mm²)
ε = 0.00222 m/m
stretch = length∙ε
stretch = 3m ∙ 0.00222
stretch = 0.0067m = 6.7mm